Aleksey Midenkov 4946e66139 MDEV-41621 Stored generated BLOB column is wrong on REPLACE into versioned table ...

REPLACE into a system-versioned table turns the conflicting row into
history in TABLE::delete_row(): it saves the new row into record[2],
restores the conflicting row from record[1] and sets its row_end with
vers_update_end(). The VCOL_UPDATE_FOR_WRITE computation in
vers_update_end() also recomputes stored generated columns. When
Field_blob::store() copies the value into Field_blob::value (e.g. on a
character set conversion), it overwrote the buffer that the stored
generated blob of the new row in record[2] points to, and the new row
was written with the value of the history row. The index on the column
holds the same value, so CHECK TABLE does not detect it.

remember_blob_values(), which keeps Field_blob::value around
vers_update_end() in TABLE::delete_row() and vers_insert_history_row()
and around update_generated_fields() in period_make_insert(), covered
only virtual columns.

The fix adds the with_stored parameter to remember_blob_values(),
restore_blob_values() and free_blob_values(), which also covers stored
generated blob columns. TABLE::delete_row(), vers_insert_history_row()
and period_make_insert() use it and size the storage by
TABLE_SHARE::virtual_fields, the number of all generated columns.

2026-10-22 18:26:14 +03:00

186 KiB

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